Mutagens protein

Thus, the generation of the specific suppressor tRNA, its acylation with the unnatural residue, and the synthesis of sufficient amount of mutagenized protein are the key steps of the entire methodology, more recently expanded in some technical aspects from its original design [101-103],... 

The key to hexavalent chromium s mutagenicity and possible carcinogenicity is the abiHty of this oxidation state to penetrate the cell membrane. The Cr(VI) Species promotes DNA strand breaks and initiates DNA—DNA and DNA-protein cross-links both in cell cultures and in vivo (105,112,128—130). The mechanism of this genotoxic interaction may be the intercellular reduction of Cr(VI) in close proximity to the nuclear membrane. When in vitro reductions of hexavalent chromium are performed by glutathione, the formation of Cr(V) and glutathione thiyl radicals are observed, and these are beHeved to be responsible for the formation of the DNA cross-links (112). 

Ethylene oxide has been shown to produce mutagenic and cytogenic effects in a variety of test systems (226). An increased frequency of chromosomal aberrations in peripheral lymphocytes of monkey exposed to ethylene oxide for 104 weeks has been reported (240). In mice, it is an effective inducer of chromosome breaks leading to dominant-lethal mutations. In addition, ethylene oxide has been shown to induce heritable effects in the heritable translocation test conducted in mice exposed to ethylene oxide by inhalation (241,242). In this study, male mice were exposed to ethylene oxide ranging from 165 to 300 ppm for 6 h per day 5 or 7 days/week for 8.5 weeks. Ethylene oxide has also been shown to bind to proteins (243) as well as to DNA (244). Several studies on ethylene oxide-exposed workers have demonstrated an increased incidence of chromosomal aberrations and sister chromatid exchanges the relevance of such effects to human health evaluation is currendy uncertain. 

Hahnel, A.C., Gifford, D.J., Heikkila, J.J., Schultz, G.A. (1986). Expression of the major heat shock protein hsp70 family during early mouse embryo development Teratogen. Carcinog. Mutagen. 6, 493-510. 

Mo, J.Y., Maki, H. and Sekiguchi, M. (1992). Hydrolytic elimination of a mutagenic nucleotide, 8-oxodGTP, by human 18-kilodalton protein sanitization of nucleotide pool. Proc. Natl Acad. Sci. USA 89, 11021-11025. 

Oxo-G (81), spiroaminodihydantoin (83), and guanidinohydantoin (85) are mutagenic lesions in duplex DNA. ° Interestingly, the electrophilic intermediate generated upon oxidation 8-oxo-G can yield protein-DNA cross-links. ... 

Wiehler J, Jung G, Seebacher C, Zumbusch A, Steipe B (2003) Mutagenic stabilization of the photocycle intermediate of green fluorescent protein (GFP). Chembiochem 4 1164—1171... 

TurboFP was also used as a basis for far-red fluorescent proteins (fRFPs). Residues surrounding the chromophore were mutagenized to create a library, which was subsequently subjected to random mutagenesis. A bright far-red variant with excitation and emission maxima at 588 and 635 nm, respectively was isolated and named Katushka [79]. This fast-maturing protein has an... 

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